package main

import "fmt"

func main() {
	planets := map[string]string {
		"Earth": "Sector ZZ9",
		"Mars": "Sector ZZ9",
	}

	planetsMarkII := planets
	planets["Earth"] = "whoops"

	fmt.Println(planets)
	fmt.Println(planetsMarkII)

	delete(planets, "Earth")
	fmt.Println(planets)
}